/**********************************************************************
Copyright (c) 2016 Advanced Micro Devices, Inc. All rights reserved.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
********************************************************************/
#include "bvhstrategy.h"

#include "../accelerator/bvh.h"
#include "../primitive/mesh.h"
#include "../primitive/instance.h"
#include "../world/world.h"

#include "../translator/plain_bvh_translator.h"

#ifdef FR_EMBED_KERNELS
#include "../kernel/CL/cache/kernels.h"
#endif

#include "device.h"
#include "executable.h"
#include <algorithm>

// Preferred work group size for Radeon devices
static int const kWorkGroupSize = 64;

namespace FireRays
{
	struct BvhStrategy::ShapeData
	{
		// Transform
		matrix minv;
		// Motion blur data
		float3 linearvelocity;
		// Angular veocity (quaternion)
		quaternion angularvelocity;
		// Shape ID
		Id id;
		// Index of root bvh node
		int bvhidx;
		// Shape mask
		int mask;
		int padding1;
	};

	struct BvhStrategy::GpuData
	{
		// Device
		Calc::Device* device;
		// BVH nodes
		Calc::Buffer* bvh;
		// Vertex positions
		Calc::Buffer* vertices;
		// Indices
		Calc::Buffer* faces;
		// Shape IDs
		Calc::Buffer* shapes;
		// Counter
		Calc::Buffer* raycnt;

		Calc::Executable* executable;
		Calc::Function* isect_func;
		Calc::Function* occlude_func;
		Calc::Function* isect_indirect_func;
		Calc::Function* occlude_indirect_func;

		GpuData(Calc::Device* d)
			: device(d)
			, bvh(nullptr)
			, vertices(nullptr)
			, faces(nullptr)
			, shapes(nullptr)
			, raycnt(nullptr)
		{
		}

		~GpuData()
		{
			device->DeleteBuffer(bvh);
			device->DeleteBuffer(vertices);
			device->DeleteBuffer(faces);
			device->DeleteBuffer(shapes);
			device->DeleteBuffer(raycnt);
			executable->DeleteFunction(isect_func);
			executable->DeleteFunction(occlude_func);
			executable->DeleteFunction(isect_indirect_func);
			executable->DeleteFunction(occlude_indirect_func);
			device->DeleteExecutable(executable);
		}
	};

	BvhStrategy::BvhStrategy(Calc::Device* device)
		: Strategy(device)
		, m_gpudata(new GpuData(device))
		, m_bvh(nullptr)
	{
#ifndef FR_EMBED_KERNELS
		char const* headers[] = { "../FireRays/src/kernel/CL/common.cl" };

		int numheaders = sizeof(headers) / sizeof(char const*);

		m_gpudata->executable = m_device->CompileExecutable("../FireRays/src/kernel/CL/bvh.cl", headers, numheaders);

#else
		m_gpudata->executable = m_device->CompileExecutable(cl_bvh, std::strlen(cl_bvh), nullptr);
#endif

		m_gpudata->isect_func = m_gpudata->executable->CreateFunction("IntersectClosest");
		m_gpudata->occlude_func = m_gpudata->executable->CreateFunction("IntersectAny");
		m_gpudata->isect_indirect_func= m_gpudata->executable->CreateFunction("IntersectClosestRC");
		m_gpudata->occlude_indirect_func = m_gpudata->executable->CreateFunction("IntersectAnyRC");
	}

	void BvhStrategy::Preprocess(World const& world)
	{
		// If something has been changed we need to rebuild BVH
		if (!m_bvh || world.has_changed() || world.GetStateChange() != ShapeImpl::kStateChangeNone)
		{
			int numshapes = (int)world.shapes_.size();
			int numvertices = 0;
			int numfaces = 0;

			// This buffer tracks mesh start index for next stage as mesh face indices are relative to 0
			std::vector<int> mesh_vertices_start_idx(numshapes);
			std::vector<int> mesh_faces_start_idx(numshapes);

			// Recreate it

			// First check if we need to use SAH
			auto builder = world.options_.GetOption("bvh.builder");
			bool enablesah = false;

			if (builder && builder->AsString() == "sah")
			{
				enablesah = true;
			}

			m_bvh.reset(new Bvh(enablesah));

			// Partition the array into meshes and instances
			std::vector<Shape const*> shapes(world.shapes_);
			
            auto firstinst = std::partition(shapes.begin(), shapes.end(),
			[&](Shape const* shape)
            {
                return !static_cast<ShapeImpl const*>(shape)->is_instance();
            });

            // Count the number of meshes
            int nummeshes = (int)std::distance(shapes.begin(), firstinst);
            // Count the number of instances
            int numinstances = (int)std::distance(firstinst, shapes.end());

			for (int i = 0; i < nummeshes; ++i)
			{
				Mesh const* mesh = static_cast<Mesh const*>(shapes[i]);

				mesh_faces_start_idx[i] = numfaces;
				mesh_vertices_start_idx[i] = numvertices;

				numfaces += mesh->num_faces();
				numvertices += mesh->num_vertices();
			}

			for (int i = nummeshes; i < nummeshes + numinstances; ++i)
			{
				Instance const* instance = static_cast<Instance const*>(shapes[i]);
				Mesh const* mesh = static_cast<Mesh const*>(instance->GetBaseShape());

				mesh_faces_start_idx[i] = numfaces;
				mesh_vertices_start_idx[i] = numvertices;

				numfaces += mesh->num_faces();
				numvertices += mesh->num_vertices();
			}

			// We can't avoild allocating it here, since bounds aren't stored anywhere
			std::vector<bbox> bounds(numfaces);
			std::vector<ShapeData> shapedata(numshapes);

			// We handle meshes first collecting their world space bounds
#pragma omp parallel for
			for (int i = 0; i < nummeshes; ++i)
			{
				Mesh const* mesh = static_cast<Mesh const*>(shapes[i]);

				for (int j = 0; j < mesh->num_faces(); ++j)
				{
					// Here we directly get world space bounds
					mesh->GetFaceBounds(j, false, bounds[mesh_faces_start_idx[i] + j]);
				}

				shapedata[i].id = mesh->GetId();
				shapedata[i].mask = mesh->GetMask();
			}

			// Then we handle instances. Need to flatten them into actual geometry.
#pragma omp parallel for
			for (int i = nummeshes; i < nummeshes + numinstances; ++i)
			{
				Instance const* instance = static_cast<Instance const*>(shapes[i]);
				Mesh const* mesh = static_cast<Mesh const*>(instance->GetBaseShape());
				
				// Instance is using its own transform for base shape geometry
				// so we need to get object space bounds and transform them manually
				matrix m, minv;
				instance->GetTransform(m, minv);

				for (int j = 0; j < mesh->num_faces(); ++j)
				{
					bbox tmp;
					mesh->GetFaceBounds(j, true, tmp);
					bounds[mesh_faces_start_idx[i] + j] = transform_bbox(tmp, m);
				}

				shapedata[i].id = instance->GetId();
				shapedata[i].mask = instance->GetMask();
			}
			
			m_bvh->Build(&bounds[0], numfaces);

			PlainBvhTranslator translator;
			translator.Process(*m_bvh);

			// Update GPU data
			// Copy translated nodes first
			m_gpudata->bvh = m_device->CreateBuffer(translator.nodes_.size() * sizeof(PlainBvhTranslator::Node), Calc::BufferType::kRead, &translator.nodes_[0]);

			// Create vertex buffer
			{
				// Vertices
				m_gpudata->vertices = m_device->CreateBuffer(numvertices * sizeof(float3), Calc::BufferType::kRead);

				// Get the pointer to mapped data
				float3* vertexdata = nullptr;
				Calc::Event* e = nullptr;
				m_device->MapBuffer(m_gpudata->vertices, 0, 0, numvertices * sizeof(float3), Calc::MapType::kMapWrite, (void**)&vertexdata, &e);

				e->Wait();
				m_device->DeleteEvent(e);

				// Here we need to put data in world space rather than object space
				// So we need to get the transform from the mesh and multiply each vertex
				matrix m, minv;

#pragma omp parallel for
				for (int i = 0; i < nummeshes; ++i)
				{
					// Get the mesh
					Mesh const* mesh = static_cast<Mesh const*>(shapes[i]);
					// Get vertex buffer of the current mesh
					float3 const* myvertexdata = mesh->GetVertexData();
					// Get mesh transform
					mesh->GetTransform(m, minv);

					//#pragma omp parallel for
					// Iterate thru vertices multiply and append them to GPU buffer
					for (int j = 0; j < mesh->num_vertices(); ++j)
					{
						vertexdata[mesh_vertices_start_idx[i] + j] = transform_point(myvertexdata[j], m);
					}
				}

#pragma omp parallel for
				for (int i = nummeshes; i < nummeshes + numinstances; ++i)
				{
					Instance const* instance = static_cast<Instance const*>(shapes[i]);
					// Get the mesh
					Mesh const* mesh = static_cast<Mesh const*>(instance->GetBaseShape());
					// Get vertex buffer of the current mesh
					float3 const* myvertexdata = mesh->GetVertexData();
					// Get mesh transform
					instance->GetTransform(m, minv);

					//#pragma omp parallel for
					// Iterate thru vertices multiply and append them to GPU buffer
					for (int j = 0; j < mesh->num_vertices(); ++j)
					{
						vertexdata[mesh_vertices_start_idx[i] + j] = transform_point(myvertexdata[j], m);
					}
				}

				m_device->UnmapBuffer(m_gpudata->vertices, 0, vertexdata, &e);

				e->Wait();
				m_device->DeleteEvent(e);
			}

			// Create face buffer
			{
				struct Face
				{
					// Up to 3 indices
					int idx[3];
					// Shape index
					int shapeidx;
					// Primitive ID within the mesh
					int id;
					// Idx count
					int cnt;
				};

				// Create face buffer
				m_gpudata->faces = m_device->CreateBuffer(numfaces * sizeof(Face), Calc::BufferType::kRead);

				// Get the pointer to mapped data
				Face* facedata = nullptr;
				Calc::Event* e = nullptr;

				m_device->MapBuffer(m_gpudata->faces, 0, 0, numfaces * sizeof(Face), Calc::BufferType::kWrite, (void**)&facedata, &e);

				e->Wait();
				m_device->DeleteEvent(e);

				// Here the point is to add mesh starting index to actual index contained within the mesh,
				// getting absolute index in the buffer.
				// Besides that we need to permute the faces accorningly to BVH reordering, whihc
				// is contained within bvh.primids_
				int const* reordering = m_bvh->GetIndices();
				for (int i = 0; i < numfaces; ++i)
				{
					int indextolook4 = reordering[i];

					// We need to find a shape corresponding to current face
					auto iter = std::upper_bound(mesh_faces_start_idx.cbegin(), mesh_faces_start_idx.cend(), indextolook4);

					// Find the index of the shape
					int shapeidx = static_cast<int>(std::distance(mesh_faces_start_idx.cbegin(), iter) - 1);

					// Get the mesh directly or out of instance
					Mesh const* mesh = nullptr;
					if (shapeidx < nummeshes)
					{
						mesh = static_cast<Mesh const*>(shapes[shapeidx]);
					}
					else
					{
						mesh = static_cast<Mesh const*>(static_cast<Instance const*>(shapes[shapeidx])->GetBaseShape());
					}

					// Get vertex buffer of the current mesh
					Mesh::Face const* myfacedata = mesh->GetFaceData();
					// Find face idx
					int faceidx = indextolook4 - mesh_faces_start_idx[shapeidx];
					// Find mesh start idx
					int mystartidx = mesh_vertices_start_idx[shapeidx];

					// Copy face data to GPU buffer
					facedata[i].idx[0] = myfacedata[faceidx].idx[0] + mystartidx;
					facedata[i].idx[1] = myfacedata[faceidx].idx[1] + mystartidx;
					facedata[i].idx[2] = myfacedata[faceidx].idx[2] + mystartidx;

					facedata[i].shapeidx = shapeidx;
					facedata[i].cnt = 0;
					facedata[i].id = faceidx;
				}

				m_device->UnmapBuffer(m_gpudata->faces, 0, facedata, &e);

				e->Wait();
				m_device->DeleteEvent(e);
			}

			// Create shapes buffer
			m_gpudata->shapes = m_device->CreateBuffer(numshapes * sizeof(ShapeData), Calc::BufferType::kRead, &shapedata[0]);
			// Create helper raycounter buffer
			m_gpudata->raycnt = m_device->CreateBuffer(sizeof(int), Calc::BufferType::kWrite);

			// Make sure everything is commited
			m_device->Finish(0);
		}
	}

	void BvhStrategy::QueryIntersection(std::uint32_t queueidx, Calc::Buffer const* rays, std::uint32_t numrays, Calc::Buffer *hits, Calc::Event const* waitevent, Calc::Event **event) const
    {
        auto& func = m_gpudata->isect_func;
        
		// Set args
		int arg = 0;
		int offset = 0;

		func->SetArg(arg++, m_gpudata->bvh);
        func->SetArg(arg++, m_gpudata->vertices);
        func->SetArg(arg++, m_gpudata->faces);
        func->SetArg(arg++, m_gpudata->shapes);
        func->SetArg(arg++, rays);
        func->SetArg(arg++, sizeof(offset), &offset);
        func->SetArg(arg++, sizeof(numrays), &numrays);
        func->SetArg(arg++, hits);

        size_t localsize = kWorkGroupSize;
		size_t globalsize = ((numrays + kWorkGroupSize - 1) / kWorkGroupSize) * kWorkGroupSize;

        m_device->Execute(func, queueidx, globalsize, localsize, event);
	}

    void BvhStrategy::QueryOcclusion(std::uint32_t queueidx, Calc::Buffer const* rays, std::uint32_t numrays, Calc::Buffer *hits, Calc::Event const* waitevent, Calc::Event **event) const
    {
        auto& func = m_gpudata->occlude_func;
        
        // Set args
        int arg = 0;
        int offset = 0;
        
        func->SetArg(arg++, m_gpudata->bvh);
        func->SetArg(arg++, m_gpudata->vertices);
        func->SetArg(arg++, m_gpudata->faces);
        func->SetArg(arg++, m_gpudata->shapes);
        func->SetArg(arg++, rays);
        func->SetArg(arg++, sizeof(offset), &offset);
        func->SetArg(arg++, sizeof(numrays), &numrays);
        func->SetArg(arg++, hits);
        
        size_t localsize = kWorkGroupSize;
        size_t globalsize = ((numrays + kWorkGroupSize - 1) / kWorkGroupSize) * kWorkGroupSize;
        
        m_device->Execute(func, queueidx, globalsize, localsize, event);
    }

    void BvhStrategy::QueryIntersection(std::uint32_t queueidx, Calc::Buffer const* rays, Calc::Buffer const* numrays, std::uint32_t maxrays, Calc::Buffer* hits, Calc::Event const* waitevent, Calc::Event** event) const
	{
        auto& func = m_gpudata->isect_indirect_func;
        
        // Set args
        int arg = 0;
        int offset = 0;
        
        func->SetArg(arg++, m_gpudata->bvh);
        func->SetArg(arg++, m_gpudata->vertices);
        func->SetArg(arg++, m_gpudata->faces);
        func->SetArg(arg++, m_gpudata->shapes);
        func->SetArg(arg++, rays);
        func->SetArg(arg++, sizeof(offset), &offset);
        func->SetArg(arg++, numrays);
        func->SetArg(arg++, hits);
        
        size_t localsize = kWorkGroupSize;
        size_t globalsize = ((maxrays + kWorkGroupSize - 1) / kWorkGroupSize) * kWorkGroupSize;
        
        m_device->Execute(func, queueidx, globalsize, localsize, event);
    }

    void BvhStrategy::QueryOcclusion(std::uint32_t queueidx, Calc::Buffer const* rays, Calc::Buffer const* numrays, std::uint32_t maxrays, Calc::Buffer* hits, Calc::Event const* waitevent, Calc::Event** event) const
    {
        auto& func = m_gpudata->occlude_indirect_func;
        
        // Set args
        int arg = 0;
        int offset = 0;
        
        func->SetArg(arg++, m_gpudata->bvh);
        func->SetArg(arg++, m_gpudata->vertices);
        func->SetArg(arg++, m_gpudata->faces);
        func->SetArg(arg++, m_gpudata->shapes);
        func->SetArg(arg++, rays);
        func->SetArg(arg++, sizeof(offset), &offset);
        func->SetArg(arg++, numrays);
        func->SetArg(arg++, hits);
        
        size_t localsize = kWorkGroupSize;
        size_t globalsize = ((maxrays + kWorkGroupSize - 1) / kWorkGroupSize) * kWorkGroupSize;
        
        m_device->Execute(func, queueidx, globalsize, localsize, event);
    }

}
